Welcome to the forum
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I have a masters degree, will it be hard for me to secure a job? I also have 15 years of experience in accounting and finance. I'd like to be able to work as soon as I arrive as we can't really afford to go without the income.
To be honest, I think you'll find it very difficult to get a job in March without having a visa yet - you'll have a much easier time of it if you get the visa first and then try to find a job.
Basically, without already having the visa, you may not even get a look in as you won't have evidence of the right to work in the UK and employers have to give priority to UK citizens and people with the right to work in the UK.
So, with the visa, you should be given the same consideration as UK citizens for jobs, but without it, your application may not even be considered. Also, if you have no UK work experience, that can hinder the application too.
Also, bear in mind that it can take a while to find a job - I would allow several weeks to several months to secure employment. I'm a UK citizen with two masters-level degrees in physics and it took me 2 years to find a graduate-level job (though it was during the recession)... I ended up working in retail for those 2 years, because I couldn't get any other job.